Morphological profile of the ovaries of high-yielding cows on day 0 of the induced sexual cycle

Abstract

An important part of reproduction management programmes on dairy farms is the detection of infertile cows and early re-insemination to achieve higher rates of pregnancy. The purpose of the study was to investigate the features of gonadal morphogenesis in high-yielding cows in the conditions of industrial keeping technology on day 0 of the sexual cycle in vivo in real time. Structural, comparative, and statistical methods were used, as well as biotechnical methods of palpation cyclic examination of ovaries with differential diagnosis of morphophysiological or pathomorphological indicators. The results of diagnostics of the ovaries of dairy cows (n=128) on day 0 of the induced cycle detected by step activity sensors showed a significant structural polymorphism of these organs of the reproductive system. It was found: from 66.67% to 30.77% of cows with a physiological course of the follicular phase of the cycle, i.e., on day 0, a preovulatory follicle or the beginning of ovulation on the ovaries (subject to a decrease in the number of cows suitable for insemination with increasing lactation duration from 50-75 days to 211-306 days (P<0.001). Hypogonadism was diagnosed in 19.45% of cows, and in 61.11% – ovarian dysfunctions with the manifestation of cystic follicular degeneration; 19.44% of cows at the time of the study had irreversible chronic adhesive processes of the genital tract tissues in the “ovary+oviduct” area (ovophoritis and ovosalpingitis in latent form), which allowed for pregnancy to occur, with a pronounced tendency to increase this gonadopathy with an increase in lactation (respectively: 50-75 days – 0.00%; 76-160 days – 22.22%; 161-210 days – 22.22%; 211 and more – 33.33%; p<0.05). The trend of influence of subclinical disorders in the metabolism of cows of the experimental herd on the indicators of the biochemical composition of blood serum and the symptom of ovarian dysfunctions was investigated. Thus, the in vivo morphological and pathological profile of the ovaries of high-yielding cows on day 0 of the sexual cycle was established, which allowed optimising the artificial insemination regime and reduce economically nonprofitless sperm consumption. The results can be used in the practical work of veterinary medicine doctors, researchers, and applicants for higher education in veterinary and biological science.